I think the problem with the Instagram account verification is something to do with not using the country code. At least that's what happened with me.
It was a US company, so I figured I don't need to add the country code because it should know where I live, but actually I only received my verification code when I entered the number +1 before my phone number and it worked.
So yeah, just make sure you enter your country (international dialing) code first. If you're not in the US then look up what your code is and you should be able to get into your Instagram account pretty quickly after that!
Try it out and see if it works for you too.
